An individual with colorectal cancer should be assessed by a multi-disciplinary team of specialists to determine which modality of treatment is best suited for them. Colorectal cancer treatment requires the involvement of different specialists – surgeons, medical oncologists, radiation oncologists, radiologists, nuclear medicine physicians, and palliative medicine specialists. Such multi-disciplinary care is available at SingHealth healthcare institutions. 

Surgery 

Depending on the stage of cancer, there are different approaches that the surgeon may use during surgery. 

In very early stages colorectal cancer the surgeon may only remove the cancerous growth or polyps involving only the innermost lining of the colon in a procedure called a polypectomy. 

In more advanced stages, the surgeon may remove a section of the colon or rectum that has a tumour and some surrounding tissue which includes regional lymph nodes. The remaining healthy bowels are then reconnected. 

When the healthy colon cannot be reconnected during the initial surgery, surgeons perform a stoma creation by creating an opening for the colon (or small intestines) onto the surface of the abdominal wall. A colostomy (opening in the colon) or an ileostomy (opening in the ileum small intestines) allows food waste to be removed from the body that is in then collected in a stoma bag. A stoma may be temporary or permanent. Specialist nurses are available to help patients or their caregivers with stoma maintenance and care. 

Minimally invasive surgery or laparoscopic surgery, where the surgeon performs the operation through several small incisions in the abdominal wall, may be performed. This method has been shown to minimise pain after surgery and accelerate recovery but is not suitable for all cases of colorectal cancer. 

Sometimes, chemotherapy and/or radiotherapy may be used before or after surgery. 

Increasingly, some patients with stage 4 cancer with limited spread to the liver, lung or peritoneum (oligometastatic disease) may be suitable for surgical treatments that can provide long term disease control or even cure. Our colorectal surgeons and oncologists work closely with the liver, lung and peritoneal surgeons to coordinate surgical treatments in patients with limited spread to the other organs for which curative intent surgery may still be possible. 

Chemotherapy is the use of anti-cancer drugs to destroy cancer cells. The type of chemotherapy, how it is administered, and the number of cycles required, depends on the type and stage of cancer, how well the patient responds and the side effects of treatment. Molecular profiling of the tumour is often performed to characterise each patient’s cancer to assist in selecting the medications that a patient is more likely to respond to. There are now more systemic treatment options including targeted therapy and immunotherapy, explained in more detail below. 

In patients with stage 2 and stage 3 cancer, chemotherapy (oxaliplatin, fluoropyrimidines) may be given after surgery for up to 3-6 months, to reduce the risk of recurrence and increase chances of long-term survival. Patients will be followed up for 5 years with regular physical examination, blood tests and interval radiological imaging, plus colonoscopy as indicated. 

In stage 4 disease where the cancer has spread to other organs, chemotherapy and/or targeted therapy is given to control the cancer in order to shrink the tumour, and to control the spread of cancer cells. Some treatments include chemotherapy (oxaliplatin, irinotecan and fluoropyrimidines, TAS102), anti-epidermal growth factor receptor (EGFR) monoclonal antibodies (panitumumab, cetuximab), anti-vascular endothelial growth factor (VEGF) monoclonal antibodies (bevacizumab, ramucirumab) and oral tyrosine kinase inhibitors such as encorafenib and regorafenib. On top of systemic therapy, some patients with oligometastatic disease may also be amenable to further surgical resections and/or other locoregional therapies such as ablation and radiation. Newer treatments and clinical trials may be available for some patients, and these can be discussed with your medical oncologists. 

Some side effects may be experienced with systemic treatment (mouth sores, rashes, numbness, loss of appetite, nausea/vomiting, diarrhoea, low blood counts, infections, allergic reactions and rarely organ dysfunction) but your condition will be monitored closely by your oncologists and adjusted as necessary. We also have a strong support from palliative care services, medical social services, physiotherapists, oncology specialist nurses and pharmacists that can help patients along their treatment journey. 

Radiation therapy 

Radiation or radiotherapy uses high-energy X-rays to kill cancer cells. The aim of radiotherapy is to destroy a localised area of cancer cells and spare as many normal cells as possible. Radiation therapy is sometimes used after surgery for colorectal cancer to destroy any remaining cancer cells and prevent the cancer from recurring. It may also be used to reduce the size of the rectal cancer before surgery. 

In some cases, when surgery is not an option, radiation therapy is used to control the growth of tumours which are causing pain or bleeding. 

Immunotherapy is a treatment that uses the patient’s own immune system to fight cancer. It is given intravenously and is usually used in selected cases of patients with microsatellite instability high (MSI-H) or deficient mismatch repair (dMMR) colorectal cancers. MSI-H/dMMR colorectal cancer may be linked to a hereditary type of colorectal cancer syndrome called Lynch Syndrome or may be sporadic (non-hereditary). 

Supportive (palliative) care 

Palliative care is specialised medical care that provides relief from pain and symptoms of serious illness so that a person with cancer feels better and has a better quality of life. The palliative care team of doctors, nurses and other healthcare professionals provide an additional layer of support that complements ongoing care.